The ECW World Heavyweight Championship was a professional wrestling world heavyweight championship originally used in Extreme Championship Wrestling (ECW) and later, World Wrestling Entertainment (WWE). It was the original world title of the Extreme Championship Wrestling promotion, spun off from the NWA World Heavyweight Championship. It was established under Extreme Championship Wrestling in 1994, but was originally introduced in 1992 by the promotion's precursor, Eastern Championship Wrestling. The inaugural champion was Jimmy Snuka.

The title was deactivated in 2001 when ECW went out of business. ECW was then purchased by WWE two years later during the summer of 2003. In 2006, WWE reactivated the championship as the world title of their newly established ECW brand. It was a third concurrently active world championship in the promotion, complementing the WWE Championship and World Heavyweight Championship of the other two brands, Raw and SmackDown. The ECW Championship briefly appeared as the only world title featured on the Raw brand in 2008 as a result of that year's draft. When WWE disbanded the ECW brand in 2010, the championship was subsequently retired with Ezekiel Jackson as the final champion.